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Recent posts
#71
Horn Loaded Systems / Re: B&C DE120-8 Replacement tw...
Last post by nre_admin - Jul 19, 2023, 09:09 AMFirst iteration of the network used on the both tweeter assemblies.
Here's the measured response on the B&C assy, the net produces an 18dB/octave slope starting around 8kHz. For the Klipschorn, the presumed mid-HF crossover is about 6kHz.
Here's the same set of measurements with the T35 and its net response superimposed. Under identical conditions the B&C assy has higher sensitivity thus requiring either padding of the output or turning the wick up on the mid horn output.
Here's the measured response on the B&C assy, the net produces an 18dB/octave slope starting around 8kHz. For the Klipschorn, the presumed mid-HF crossover is about 6kHz.
Here's the same set of measurements with the T35 and its net response superimposed. Under identical conditions the B&C assy has higher sensitivity thus requiring either padding of the output or turning the wick up on the mid horn output.
#72
Horn Loaded Systems / Re: B&C DE120-8 Replacement tw...
Last post by nre_admin - Jul 19, 2023, 08:56 AMNearfield measurements were taken as shown in the setup below. The mic and baffle, once spotted, were not moved during all the measurements taken, the power amplifier (Crown D-75) was set and not touched. Response plots were made using CLIO 12 at a sampling rate of 192kHz.
T35
B&C with horn flare assy
The B&C website has the datasheet for the DE120 mounted to a B&C horn. Here's the published plot from the data sheet.
Here's the no-net measured response of the B&C with the horn flare, similar to the factory response. There's a peak in the response around 16.5kHz.
T35
B&C with horn flare assy
The B&C website has the datasheet for the DE120 mounted to a B&C horn. Here's the published plot from the data sheet.
Here's the no-net measured response of the B&C with the horn flare, similar to the factory response. There's a peak in the response around 16.5kHz.
#73
Horn Loaded Systems / B&C DE120-8 Replacement tweete...
Last post by nre_admin - Jul 19, 2023, 08:13 AMI received the tweeter assembly below for measurements. It's a B&C DE120-8 with an Aluminum horn flare fabricated by Dave Ault. The flare is two pieces bolted together with Allen hd machine screws. It's pretty stout, a hog-out from either thick plate or bar stock.
Here's a side by side with the sad little EV T35. The Klipschorn, LaScala and Belle used the EV T35 for decades until it was NLA from EV. Klipsch, rather than designing or sourcing a resepctable tweeter, decided to replicate the Avedon unit.
Here's a side by side with the sad little EV T35. The Klipschorn, LaScala and Belle used the EV T35 for decades until it was NLA from EV. Klipsch, rather than designing or sourcing a resepctable tweeter, decided to replicate the Avedon unit.
#74
Passive Networks / Re: North Reading Engineering ...
Last post by nre_admin - Jul 18, 2023, 03:03 PMMike-
The sketch is incorrectly drawn. It should be P0, P1, P2 top to bottom. The table is correct however.
Apologies and good catch.
jw
The sketch is incorrectly drawn. It should be P0, P1, P2 top to bottom. The table is correct however.
Apologies and good catch.
jw
#75
Passive Networks / Re: North Reading Engineering ...
Last post by mboxler - Jul 17, 2023, 12:06 PMHey John
I'm probably reading your chart wrong, so I'm attaching two diagrams for clarification. The first shows the amp connected to P1 and GND, and the load to T3 and GND. I believe you are saying that if the voltage across P1 - GND is 10, then the voltage across the load (T3 - GND) would be 7.6. You are then saying that if the amp were connected to P0 - GND, then the voltage across the load (T3 - GND) would be 6.9.
Shouldn't the voltage across the load be increasing instead of decreasing?
Again, I may be reading you chart wrong.
Mike
I'm probably reading your chart wrong, so I'm attaching two diagrams for clarification. The first shows the amp connected to P1 and GND, and the load to T3 and GND. I believe you are saying that if the voltage across P1 - GND is 10, then the voltage across the load (T3 - GND) would be 7.6. You are then saying that if the amp were connected to P0 - GND, then the voltage across the load (T3 - GND) would be 6.9.
Shouldn't the voltage across the load be increasing instead of decreasing?
Again, I may be reading you chart wrong.
Mike
#76
Oscilloscopes, Signal Generators, FFT Analyzers, Multimeters / Re: Tek 465 Power Supply Rebui...
Last post by nre_admin - Jul 16, 2023, 05:25 PMHere's my first stab at the 465 SN 250000-up electrolytic capacitor parts list. The power supply caps are not listed here. I'll add a separate list for those.
#77
Oscilloscopes, Signal Generators, FFT Analyzers, Multimeters / Re: Tek 465 Power Supply Rebui...
Last post by nre_admin - Jul 08, 2023, 09:47 AM55VDC supply and ripple voltage.
Back in business.
Back in business.
#78
Oscilloscopes, Signal Generators, FFT Analyzers, Multimeters / Re: Tek 465 Power Supply Rebui...
Last post by nre_admin - Jul 08, 2023, 09:33 AMInstallation of new power supply filter capacitors. All are PET dielectric, 105C, Nichicon and United Chemi-con.
#79
Oscilloscopes, Signal Generators, FFT Analyzers, Multimeters / Re: Tek 465 Power Supply Rebui...
Last post by nre_admin - Jul 04, 2023, 04:45 PMTo remove these capacitors, I've had good results using both a temperature-controlled iron and a trigger actuated vacuum desoldering tool. I heat the top side of the board with the iron and use the vacuum actuated desolder unit on the bottom side. A clean-up with solder braid is all that's needed to loosen the cap and remove any residual solder from the joints. The capacitor, if done properly, will release without any distress to the board traces.
#80
Oscilloscopes, Signal Generators, FFT Analyzers, Multimeters / Re: Tek 465 Power Supply Rebui...
Last post by nre_admin - Jul 04, 2023, 04:39 PMSchematic
